Multicentric randomised trial. Patients with a high risk of developing colorectal Peritoneal Carcinomatosis (PC) after resection of their primary will be informed, will sign the consent and will be pre-registered. All patients will receive the current standard adjuvant treatment : 6 months of systemic chemotherapy (currently the Folfox-4 regimen which could be modified if the standard is modified). Then a work-up is done to exclude recurrence. The likelihood of a recurrence is low but if this occurs, the patient will not be randomised and will be treated with the best known treatment. If the work-up is negative, patients will be randomised to surveillance alone (control group) or exploratory laparotomy + HIPEC (experimental group).